When I think about it, there aren't many sites I visit whilst listening to music.
Most of them involve watching/listening to some form of video and/or audio file and it's frustrating to have to continuously pause & play your music in between videos or whatnot.
The only sites I can think of when jamming to some sick assed music aside from this site are usually forum sites just to see what's up.
For example: Facepunch and the occasional Game Trailers visit (I find it absolutely hilarious how everyone on game trailers accuses one another of being a troll whenever a comment about a game sounds even slightly negative.)
Other non-forum sites are:
Facebook.com and xkcd.com.
That's about it; and yes I know, I'm disappointed in my internet surfing skills too. :'(
My question to you is, what are the web sites you guys like to visit whilst listening to music? I'm hoping we can expand our site viewings on this particular subject...